10 August, 2022
This document summarizes estimates of change in mature individuals over time for Pacific salmon Designatable Unit (DU) and associated probable COSEWIC status designation. Data sources are detailed here and all code to reproduce the analyses in this document is here. These materials are solely intended to support the Marine Fishes sub-committee of COSEWIC in identifying high priority DUs for COSEWIC to consider when conducting formal status assessments.
Initial thoughts on potential decision nodes in the prioritization process.
Have DUs been formally defined by COSEWIC? Chinook, sockeye, and coho salmon DUs have been defined (reports available here), formal pink and chum DU identification is in progress. If yes then proceed.
Is information on mature individuals over time available at the DU scale? If yes then proceed.
Has DU been previously assessed by COSEWIC? If yes then consider a re-assessment, otherwise proceed except for DUs that have already been approved for a status assessment.
What is the DUs probable designation based on percentage change in mature individuals over past three generations? If special concern, threatened or endangered then proceed.
Are there spatial considerations? Are there commonalities in threats, designations, and/or data landscape at a regional scale that suggest a group of DUs should be bundled together?
**Figure 1**. Status of all DUs. For DUs that have been previously
assessed by COSEWIC the official status is shown, otherwise probable
status is inferred based on percent change in mature individual
abundance over the most recent three generations of data.
**Figure 2**. Probable status of unassessed Pacific salmon DUs
(excluding those previously assessed by CPOSEWIC or recommended for
status assessment) based on rate of change in mature individuals over
most recent three generations.
The summaries for all DUs are available in a table here. A preview of the table is shown below.
## Region DU Species Generation length COSEWIC status % Change (recent)
## 1 Fraser CK1 Chinook 5 Threatened 457
## 2 Fraser CK10 Chinook 5 Threatened -63
## 3 Fraser CK11 Chinook 5 Endangered -46
## 4 Fraser CK12 Chinook 4 Not at risk -22
## 5 Fraser CK13 Chinook 5 Endangered -15
## 6 Fraser CK14 Chinook 4 Endangered -89
## % Change (all) Recent abundance Last year Probable status Status
## 1 32 103 2018 Not at risk Threatened
## 2 -55 4684 2018 Threatened Threatened
## 3 -14 7339 2018 Special concern Endangered
## 4 4 37005 2018 Not at risk Not at risk
## 5 15 922 2018 Not at risk Endangered
## 6 -55 4 2018 Endangered Endangered
